1. Field of the Invention
The invention relates to wax-like β-ketocarbonyl-functional organosilicon compounds, and to a process for their preparation.
2. Description of the Related Art
The standard preparation of silicone waxes is by hydrosilylation of hydrogensiloxane and alpha-olefins. The linear polymer thusly obtained consists predominantly of alkylmethylsiloxane units. On account of the required minimum chain length of the alkyl radicals, their fraction of the overall mass is very high, in most cases >70%, meaning that the silicone character is less marked. Moreover, the standard process has the inherent disadvantage of a hydrosilylation with residual content of SiH groups and the heavy metal content of the wax in the form of platinum compounds, which are required as catalysts.
DE 102 96 506 T5 describes linear silicone waxes which comprise at least 25 mol% of RR1SiO units, in which R is a C1-C8-alkyl radical or C6-C10-aryl radical, and R1 corresponds to a long-chain organic radical having at least 16 carbon atoms and which may contain 1 to 10 heteroatoms. These waxes comprise a high percentage of long-chain organic radicals in the lateral position of the siloxane chain. Compared with siloxanes with a high fraction of dimethylsiloxane units, such polymers are complex and expensive to produce.
EP 1 624 010 A1 likewise describes linear silicone waxes which, apart from C1-C20-substituents, also contain substituents which consist of at least one behenic ester group bonded to the siloxane chain via a pentaerythritol radical. Although the molar amount can vary over a wide range, considerable expenditure is associated just with producing this large substituent. Finally, the aliphatically unsaturated behenic ester is bonded to the siloxane via hydrosilylation, as a result of which the silicone wax again contains heavy metal from platinum catalyst. Since the reaction components are not very soluble in one another, relatively large amounts of solvent are required to carry out the hydrosilylation. One production variant is based on the esterification of a behenic ester carbinol with anhydridosiloxane. In this variant, although no additional heavy metal compound is required, it is not possible to also dispense with solvents.
In a similar manner, according to US 2003/096919 A1, silicone waxes are prepared from an SiH—, SH— or amino-functional siloxane and a fatty acid or fatty alcohol component which additionally also contains an aliphatic double bond. A preferred fatty component is a behenic compound. The linear siloxanes are typically short-chain, and the organic fraction of the wax products is therefore in most cases considerably more than 50% by weight, as a result of which the siloxane character is not very marked.
WO 2007/060113 A2 describes a process for the preparation of β-ketocarbonyl-functional organosilicon compounds, in which diketenes are reacted with organosilicon compounds having amino groups. Here, oils are obtained.